1. Field of the Invention
The present invention relates to an apparatus for multi-color printing on the surfaces of bodies of rotation and, more particularly, to a multi-color printing apparatus for multi-color printing on the surfaces of cylindrical articles such as containers or tubes made of synthetic resins by applying desired colors of ink of ultraviolet-ray set type one by one to their surfaces while being set after each of the ink applications.
2. Description of the Prior Art
It has been conducted according to the prior art to multi-color print the outer circumferences of the synthetic resin articles such as the cylindrical containers or tubes being rotationally driven with multiple colors of ultraviolet-ray set type ink.
According to this multi-color printing process of the prior art, however, the ink in a color to appear is prepared in advance, and different colors of ink are positioned in parallel with the outer circumferences of the articles, but new ink in a different color is not additionally applied to the ink which has already been applied.
If the ink in a different color is additionally applied to the printed ink, more specifically, there arise disadvantages that the overlapped colors of in are mixed to allow an unexpected color to appear and that a printer to print a desired color of ink has its branket blotted with another color of ink, which has already been applied to an article, until the ink in the different color will mixed with the ink in the printer under consideration.
According to the prior art, therefore, it is necessary to prepare multiple colors of ink mixed in advance. This necessity requires not only a number of printers but also a number of printing operations. Thus, the prior art has defects that the cost for facilities is enormously high and that the number of the printing steps required for on article is enlarged.
Even if it is considered that the different colors of ink be not overlapped, moreover, the bracket is blotted with a portion of the ink having been applied to the surface of the article so that the mixture of the ink cannot be completely prevented. In addition, it is necessary to periodically replace the ink and to rinse the printer as a whole.
Even if numerous colors of ink are prepared in advance, still moreover, it is impossible to allow a color of such a half tone as has its color continuously changed. As a result, the color pattern to appear has to be of a uniformity which is difficult to obtain.